The present invention relates to water-dispersible granules comprising at least one fragrance in a water-soluble or water-dispersible organic polymer matrix, to a process for preparing them, to their use as fragrancing agents in detergent or cosmetic compositions and to laundry detergent compositions or cosmetic compositions comprising said particles.
The fragrancing of detergent washing compositions, in particular for washing laundry, requires a certain number of constraints that are more or less important depending on the technico-economic and marketing objectives of the formulator.
One of the first problems posed is to find a suitable means of adding and distributing the liquid fragrance on the detergent powder.
The fragrance is generally finely sprayed, continuously, onto the complete formulated powder, which transits in any transporter, between the site of manufacture and the site of packaging. Pneumatic transporters can be used for this operation, or alternatively xe2x80x9cair liftxe2x80x9d systems. It is necessary for the washing product formulated to be sufficiently cooled, in particular when the manufacturing process is a spraying process, and for the mixing system to permit only a minimal loss of fragranced substance, which is among the most expensive components of the formulation. Respecting the dosage (percentage of fragrance relative to the powder) is one of the factors that is difficult to control and which needs investigating to be improved both on account of the problems of cost and on account of the problems of consistency of quality.
Formulating the composition as a particulate solid can represent a first improvement to this level of process for manufacturing washing products.
Another problem of the fragrancing of washing products is that of the stability of the fragrance (and of all of the xe2x80x9cnotesxe2x80x9d it releases) during storage of the washing product in its packaging.
Specifically, the components of washing products are themselves very varied and their chemical natures are very diverse and may be corrosive, or even incompatible, with the fragranced composition, which comprises chemically fragile components.
Modern washing products often contain bleaching systems based on products which release hydrogen peroxide, followed by active oxygen. This is the most destabilizing factor for the fragrances.
The alkalinity of the compositions is also a factor with regard to degradation of the fragrance.
Highly absorbent products such as silicas, clays or zeolites can selectively and to a greater or lesser extent absorb the fragrance or one of its components and thereby contribute toward modifying or impairing it.
Similarly, the water of crystallization, free water, surfactants and sequestering agents, which are always present in detergent compositions, may interfere negatively with the fragranced compositions.
A third problem, or a third requirement, encountered in the field of fragrancing washing products is the fact that the perception of the odor chosen, which is one of the methods by which the purchaser recognizes the washing product, should be effective in all the lifecycles of the washing product, and even beyond.
In particular, the odor of the fragrance, or at the very least a fraction of this odor, should be perceptible in the shop in which the washing product is presented for purchase, during the shelf life of the packet (even opened), during the washing itself, from the washing machine, during the operations of drying, ironing and tidying away of the washed articles, in the wardrobe, and finally during the wearing or use of the laundry.
Such a series of requirements is obviously not easy to satisfy, but among the means which need to be deployed to attend to this satisfaction, coating and encapsulation, which improve the stability on storage and can under certain conditions allow a release of the fragrance during washing, are one of the most important and most effective means.
Several methods for formulating fragrances in solid form have been attempted in the past or very recently by fragrance manufacturers or by washing product manufacturers to partially or totally solve these problems.
One of the first means is to use the absorbent properties of certain porous supports, such as silicas, clays, natural or synthetic zeolites, starches, carboxymethylcellulose, urea, soluble inorganic phosphates, etc.
However, there are numerous drawbacks with these formulation methods, in particular the fact of dividing and spreading the fragrance over very large contact surfaces, and thus of increasing the risks of oxidation at the same time as the area for exchange between the fragrance and the air, and also the risk of selectively retaining one or more components, with restitution of a modified odor.
Simple absorption allows formulation in solid form, but is often insufficient for protecting the fragrance during storage. There should also be recourse to a coating of the fragrance/support assembly.
Another formulation method is the use of products of specific molecular structure making it possible to create a cavity for receiving the fragrances, for example products such as cyclodextrins. The drawback, besides the cost, is the difficulty in introducing complex compositions based on products of very different and dissimilar molar mass and steric bulk.
Organic matrices composed of PEG or of paraffins whose molecular mass is sufficient for them to be solid at ordinary temperature, have also been proposed for solidifying fragranced compositions, with advantages but also drawbacks, in particular that of only partially releasing the fragrance, or the fact that molten phases of the coating products need to be used.
Sophisticated methods that are difficult to control, such as the techniques of microencapsulation by interfacial polycondensation, have also been put forward for obtaining encapsulated fragrances, but their cost and their complexity have not facilitated their development.
Finally, the use of preformed microcapsules, either mineral or polymeric, which are optionally mechanically disintegrable, have also been envisaged, without great commercial success, probably for economic reasons.
The Applicant has found a water-dispersible solid formulation for liquid fragrances, by encapsulation with a protective matrix which becomes located outside the droplets of finely divided fragrance; in this way, said matrix coats the fragrance, protects it and at the same time allows it to change to solid form.
A first subject of the invention consists of water-dispersible granules comprising
at least one hydrophobic fragrance (P), in the form of droplets, which is finely divided in and encapsulated by a water-soluble or water-dispersible solid organic matrix (MO) chosen from
water-soluble or water-dispersible polypeptides (PP) of plant or synthetic origin
polyelectrolytes (PE) belonging to the family of weak polyacids
or mixtures thereof,
and at least one emulsifier (AE) at the droplet/matrix interface.
For good implementation of the invention, said water-dispersible granules comprise
from 5% to 90%, preferably from 25% to 70%, of their weight of fragrance (P),
from 5% to 90%, preferably from 25% to 70%, of their weight of water-soluble or water-dispersible organic matrix (MO),
from 0.02% to 20%, preferably from 0.1% to 10%, of their weight of emulsifier (AE), said percentages being expressed by weight of solids.
Said droplets can have a mean particle size from about 0.1 xcexcm to 10 xcexcm, preferably from about 0.2 xcexcm to 5 xcexcm.
The term xe2x80x9cfragrancexe2x80x9d means either a fragranced essence or, more generally, a complex composition obtained using many odoriferous products as a mixture and excipient products which ensure its homogeneity.
Said fragrances according to the invention are isotropic and hydrophobic compounds. Their solubility in water at pH 7 does not exceed 10% by weight.
The mixture of odoriferous products can comprise a large number of constituents, chosen so as to obtain the desired fragranced notes for the intended use, public and market. Natural products (for example plant or animal essences obtained by extraction with steam or by alcoholic extraction, which are themselves already mixtures) or synthetic products which may be aliphatic or aromatic ketones, aliphatic or aromatic aldehydes, condensation products of aldehydes and amines, aromatic or aliphatic lactones, aromatic or aliphatic ethers or esters, aliphatic alcohols of varied molecular mass, linear, cyclic or aromatic saturated or unsaturated hydrocarbons, and terpines, which may or may not be polynuclear, are generally found.
The compositions of the most sophisticated fragrances can contain up to a hundred ingredients.
As examples of odoriferous compounds, mention may be made of:
hexylcinnamaldehyde, 2-methyl-3-(para-tert-butyl-phenyl)propionaldehyde
7-acetyl-1,2,3,4,5,6,7,8-octahydro-1,1,6,7-tetra-methylnaphthalene
benzyl salicylate; 7-acetyl-1,1,3,4,4,6-hexamethyltetralin
para-tert-butylcyclohexyl acetate
methyl dihydrojasmonate; beta-naphthyl methyl ether methyl beta-naphthyl ketone; 2-methyl-2-(para-isopropylphenyl)propionaldehyde
1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyran
dodecahydro-3a,6,6,9a-tetramethylnaphtho[2,1-b]bifuran; anisaldehyde
coumarin; cedrol; vanillin; cyclopentadecanolide tricyclodecenyl acetate; tricyclodecenyl propionate; phenylethyl alcohol
terpineol; linalool; linalyl acetate; geraniol; nerol 2-(1,1-dimethylethyl)cyclohexanol acetate; benzyl acetate; terpenes (orange)
eugenol; diethyl phthalate
essential oils, resins or resinoids (oil of orange, lemon, patchouli, Peru balm, Oilbanum resinoid, styrax, coriander, lavandin, lavender, etc.).
Other examples of odoriferous compounds are described in H 1468 (United States Statutory Invention Registration).
Among the water-soluble or water-dispersible synthetic polypeptides (PP) which can constitute the matrix, mention may be made of homopolymers and copolymers derived from the polycondensation of amino acids, in particular of aspartic acid and glutamic acid or precursors of said amino diacids, and hydrolysis. These polymers can be not only homopolymers derived from aspartic acid or glutamic acid but also copolymers derived from aspartic acid and glutamic acid in all proportions, or copolymers derived from aspartic acid and/or glutamic acid and from other amino acids. Among the copolymerizable amino acids which may be mentioned are glycine, alanine, leucine, isoleucine, phenylalanine, methionine, histidine, proline, lysine, serine, threonine, cysteine, etc.
Among the polypeptides (PP) of plant origin, mention may be made of water-soluble or water-dispersible proteins of plant origin. They are preferably hydrolyzed; their degree of hydrolysis is preferably less than or equal to 40%, for example from 5% to less than 40%.
Among the proteins of plant origin which may be mentioned as a guide are proteins originating from proteaginous seeds, in particular those of pea, bean, lupin, haricot and lentil; proteins originating from cereal seeds, in particular those of wheat, barley, rye, corn, rice, oat and millet; proteins originating from oleaginous seeds, in particular those of soya, groundnut, sunflower, rape and coconut; proteins originating from leaves, in particular from alfalfa and nettles; and proteins originating from underground reserves of plant organs, in particular those of potato and beetroot.
The protein of plant origin more particularly originates from soya or wheat.
The polyelectrolyte (PE) can be chosen from those derived from the polymerization of monomers which have the general formula
(R1)(R2)Cxe2x95x90C(R3)COOH
in which formula R1, R2 and R3 are identical or different and represent
a hydrogen atom,
a hydrocarbon-based radical containing from 1 to 4 carbon atoms, preferably methyl,
a xe2x80x94COOH function,
a radical xe2x80x94Rxe2x80x94COOH, in which R represents a hydrocarbon-based residue containing from 1 to 4 carbon atoms, preferably an alkylene residue containing 1 or 2 carbon atoms, most particularly methylene.
Non-limiting examples which may be mentioned are acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and crotonic acid.
Copolymers obtained from monomers corresponding to the above general formula and those obtained using these monomers and other monomers, in particular vinyl derivatives such as vinyl alcohols and copolymerizable amides such as acrylamide or methacrylamide, are also suitable for use. Mention may also be made of the copolymers obtained from alkyl vinyl ether and from maleic acid as well as those obtained from vinylstyrene and maleic acid, which are described in particular in the Kirk-Othmer encyclopedia entitled xe2x80x9cEncyclopedia of Chemical Technologyxe2x80x9dxe2x80x94Volume 18xe2x80x943rd Editionxe2x80x94Wiley Interscience Publicationxe2x80x941982.
The preferred polyelectrolytes have a low degree of polymerization. The weight-average molecular mass of the polyelectrolytes is more particularly less than 20,000 g/mol. Preferably, it is between 1000 and 5000 g/mol.
The emulsifiers (AE) which may be present are nonionic, ionic or amphoteric emulsifiers.
When said matrix (MO) is made of a polypeptide (PP), said emulsifier (AE) is chosen from ionic and amphoteric emulsifiers. When said matrix (MO) is a polyelectrolyte (PE), said emulsifier (AE) is chosen from nonionic and amphoteric emulsifiers.
Among the nonionic emulsifiers which may be mentioned in particular are polyoxyalkylenated derivatives such as
ethoxylated or ethoxy-propoxylated fatty alcohols
ethoxylated or ethoxy-propoxylated triglycerides
ethoxylated or ethoxy-propoxylated fatty acids
ethoxylated or ethoxy-propoxylated sorbitan esters
ethoxylated or ethoxy-propoxylated fatty amines
ethoxylated or ethoxy-propoxylated di(1-phenylethyl)-phenols
ethoxylated or ethoxy-propoxylated tri(1-phenyl-ethyl)phenols
ethoxylated or ethoxy-propoxylated alkylphenols.
The number of oxyethylene (OE) and/or oxypropylene (OP) units in these nonionic surfactants usually ranges from 2 to 100 depending on the desired HLB (hydrophilic/lipophilic balance). The number of OE and/or OP units is more particularly between 2 and 50.
The number of OE and/or OP units is preferably between 10 and 50.
The ethoxylated or ethoxy-propoxylated fatty alcohols generally comprise from 6 to 22 carbon atoms, the OE and OP units being excluded from these numbers. These units are preferably ethoxylated units.
The ethoxylated or ethoxy-propoxylated triglycerides can be triglycerides of plant or animal origin (such as lard, tallow, groundnut oil, butter oil, cottonseed oil, flax oil, olive oil, fish oil, palm oil, grapeseed oil, soybean oil, castor oil, rapeseed oil, copra oil or coconut oil and are preferably ethoxylated.
The ethoxylated or ethoxy-propoxylated fatty acids are esters of fatty acids (such as, for example, oleic acid or stearic acid), and are preferably ethoxylated.
The ethoxylated or ethoxy-propoxylated sorbitan esters are cyclized sorbitol esters of fatty acids comprising from 10 to 20 carbon atoms such as lauric acid, stearic acid or oleic acid, and are preferably ethoxylated.
In the present invention, the term xe2x80x9cethoxylated triglyceridexe2x80x9d targets not only the products obtained by ethoxylation of a triglyceride with ethylene oxide but also those obtained by transesterification of a triglyceride with a polyethylene glycol.
Similarly, the term xe2x80x9cethoxylated fatty acidxe2x80x9d includes not only the products obtained by ethoxylation of a fatty acid with ethylene oxide but also those obtained by transesterification of a fatty acid with a polyethylene glycol.
The ethoxylated or ethoxy-propoxylated fatty amines generally contain from 10 to 22 carbon atoms, the OE and OP units being excluded from these numbers, and are preferably ethoxylated.
The ethoxylated or ethoxy-propoxylated alkyl phenols are generally 1 or 2 linear or branched alkyl groups containing 4 to 12 carbon atoms. Examples which may be mentioned in particular are octyl, nonyl or dodecyl groups.
Examples of nonionic surfactants from the group of ethoxy or ethoxy-propoxylated alkylphenols, ethoxylated di(1-phenylethyl)phenols and ethoxy or ethoxy-propoxylated tri(1-phenylethyl)phenols which may be mentioned in particular are di(1-phenylethyl)phenol ethoxylated with 5 OE units, di(1-phenylethyl)phenol ethoxylated with 10 OE units, tri(1-phenylethyl)phenol ethoxylated with 16 OE units, tri(1-phenylethyl)phenol ethoxylated with 20 OE units, tri(1-phenylethyl)phenol ethoxylated with 25 OE units, tri(1-phenylethyl)phenol ethoxylated with 40 OE units, tri(1-phenylethyl)phenols ethoxy-propoxylated with 25 OE+OP units, nonylphenol ethoxylated with 2 OE units, nonylphenol ethoxylated with 4 OE units, nonylphenol ethoxylated with 6 OE units, nonylphenol ethoxylated with 9 OE units, nonylphenols ethoxy-propoxylated with 25 OE+OP units, nonylphenols ethoxy-propoxylated with 30 OE+OP units, nonylphenols ethoxy-propoxylated with 40 OE+OP units, nonylphenols ethoxy-propoxylated with 55 OE+OP units and nonylphenols ethoxy-propoxylated with 80 OE+OP units.
Among the anionic emulsifiers which may be mentioned are water-soluble salts of alkyl sulfates and of alkyl ether sulfates, alkyl isothionates and alkyl taurates or salts thereof, alkyl carboxylates, alkyl sulfosuccinates or alkyl succinamates, alkyl sarcosinates, alkyl derivatives of protein hydrolyzates, acyl aspartates, and alkyl and/or alkyl ether and/or alkylaryl ether phosphate esters.
The cation is generally an alkali metal or alkaline-earth metal, such as sodium, potassium, lithium or magnesium, or an ammonium group NR4+ with R, which may be identical or different, representing an alkyl radical substituted or unsubstituted with an oxygen or nitrogen atom.
Among the cationic emulsifiers which may be mentioned are alkyldimethylbenzylammonium halides, alkyldimethylethylammonium halides, etc.
Among the amphoteric surfactants which may be mentioned are alkylbetaines, alkyldimethylbetaines, alkylamidopropylbetaines, alkylamidopropyldimethyl-betaines, alkyltrimethylsulfobetaines, imidazoline derivatives such as alkyl amphoacetates, alkyl amphodiacetates, alkyl amphopropionates, alkyl amphodipropionates, alkylsultaines or alkylamidopropylhydroxysultaines, the condensation products of fatty acids and of protein hydrolyzates, amphoteric derivatives of alkylpolyamines such as Amphionic XL(copyright) sold by Rhxc3x4ne-Poulenc, Ampholac 7T/X(copyright) and Ampholac 7C/X(copyright) sold by Berol Nobel, and proteins or protein hydrolyzates.
According to one embodiment variant, up to 50% of the weight of the matrix (MO) can consist of a water-soluble or water-dispersible ose, oside or polyholoside (O).
Among the oses (O) which may be mentioned are aldoses such as glucose, mannose, galactose and ribose, and ketoses such as fructose.
Osides are compounds which result from the condensation, with elimination of water, of ose molecules with each other or of ose molecules with non-carbohydrate molecules. Among the preferred osides are holosides which are formed by combining exclusively carbohydrate units and more particularly oligoholosides (or oligosaccharides) which comprise only a limited number of these units, i.e. a number generally less than or equal to 10. Examples of oligoholosides which may be mentioned are sucrose, lactose, cellobiose, maltose and trehalose.
The water-soluble or water-dispersible polyholosides (or polysaccharides) are highly depolymerized; they are described, for example, in the book by P. Arnaud entitled xe2x80x9cCours de Chimie Organiquexe2x80x9d, edited by Gaultier-Villars, 1987. These polyholosides more particularly have a weight-average molecular mass of less than 20,000 g/mol.
Non-limiting examples of highly polymerized polyholosides which may be mentioned are dextran, starch, xanthan gum and galactomannans such as guar or carob, these polysaccharides preferably having a melting point of greater than 100xc2x0 C. and a solubility in water of between 50 g/l and 500 g/l.
A second subject of the invention consists of a two-step process for preparing water-dispersible granules, comprising
at least one hydrophobic fragrance (P), in the form of droplets, which is finely divided in and encapsulated by a water-soluble or water-dispersible solid organic matrix (MO), chosen from
water-soluble or water-dispersible polypeptides (PP) of plant or synthetic origin
polyelectrolytes (PE) belonging to the family of weak polyacids
or mixtures thereof,
and at least one emulsifier (AE) at the droplet/matrix interface,
the first step consisting in preparing an emulsion in water comprising at least one hydrophobic fragrance (P), at least one emulsifier (AE) and said water-soluble or water-dispersible organic matrix (MO), the second step consisting in drying said emulsion until a granulate is formed.
The term xe2x80x9chydrophobicxe2x80x9d is synonymous with solubility in water at pH 7 not exceeding 10% by weight.
The relative amounts of fragrance (P), of emulsifier (AE) and of water-soluble or water-dispersible organic matrix (MO) used are such that said emulsion, expressed as solids, comprises
from 5% to 90%, preferably from 25% to 70%, of their weight of hydrophobic fragrance (P),
from 5% to 90%, preferably from 25% to 70%, of their weight of water-soluble or water-dispersible organic matrix (MO),
from 0.02% to 20%, preferably from 0.1% to 10%, of their weight of emulsifier (AE),
said percentages being expressed by weight of solids.
The amount of solids in the emulsion is generally between 10% and 70% by weight and preferably between 20% and 60% by weight.
Any method for preparing emulsions which is known to those skilled in the art and which is described in xe2x80x9cEncyclopedia of Emulsions Technologyxe2x80x9d, volumes 1 to 3 by Paul Becher, published by Marcel Dekker Inc., 1983, can be used.
Thus, the method known as direct in-phase emulsification is suitable for preparing the granules according to the invention. It is briefly recalled that this method consists in preparing a mixture containing water, the emulsifier(s), the water-soluble or water-dispersible matrix (MO) and then in introducing the fragrance in liquid form, with stirring.
The emulsion can also be prepared using colloidal mills such as the Menton Gaulin and Microfluidizer (Microfluidics) mills.
The mean particle size of the emulsion is generally between 0.1 and 10 micrometers and preferably between 0.2 and 5 micrometers.
The emulsification can be carried out at a temperature in the region of ambient temperature, although lower or higher temperatures can be envisaged.
The second step of the preparation process according to the invention consists in drying the emulsion thus formulated in order to obtain granules.
The method used to eliminate water from the emulsion and to obtain granules can be carried out by any means known to those skilled in the art.
For example, lyophilization, which corresponds to a step of freezing followed by a step of sublimation, or alternatively spray-drying, are suitable.
These methods of drying, and more particularly spray-drying, are particularly indicated since they make it possible to store the emulsion in its native form and to obtain granules directly. Water-soluble or water-dispersible proteins of plant origin are particularly suitable for spray-drying, since they are particularly stable.
The spray-drying can be carried out in the usual manner in any known apparatus such as, for example, a spraying tower combining a spraying operation carried out using a nozzle or a turbomixer with a stream of hot gas.
The operating conditions depend on the nature of the matrix, on the heat-sensitivity of the fragrance and on the sprayer used; these conditions are generally such that the temperature of the product assembly during drying does not exceed 150xc2x0 C., and preferably does not exceed 110xc2x0 C.
Unexpectedly, the spray-drying in a stream of hot gas takes place without any impairment of the fragrance.
It should be noted that additives such as anticaking agents can be incorporated into the granules at the time of the second drying step. It is recommended to use a filler chosen in particular from calcium carbonate, kaolin, silica, bentonite, etc.
The composite particles obtained can be redispersed in water.
The release of the fragrance during the redispersion operation can be controlled by the choice of organic matrix (MO), by selecting a matrix of gradual or slow solubility.
Another subject of the invention consists of the use of said dispersible granules as fragrancing agents in cosmetic compositions and in particular in detergent compositions for washing laundry (industrial or domestic washing).
According to the invention, said granules can be used in a proportion from about 0.01% to 0.5%, preferably from 0.05% to 0.2%, by weight relative to the detergent composition.
A final subject of the invention consists of cosmetic compositions and in particular of detergent compositions for washing laundry (industrial or domestic washing), comprising said fragrance-based dispersible granules.
According to the invention, the detergent compositions can contain about 0.01% to 0.5%, preferably from 0.05% to 0.2%, of their weight of fragrance-based dispersible granules.
The detergent compositions according to the invention comprise at least one surfactant, in an amount generally from about 5% to 60% by weight, preferably from 8% to 50% by weight.
Among these surfactants, mention may be made of the anionic or nonionic surfactants usually used in the field of detergency for washing laundry. The detergent compositions which form the subject of the invention can also comprise common additives, such as inorganic or organic detergent adjuvants (xe2x80x9cbuildersxe2x80x9d) in an amount such that the total amount of detergent adjuvant is from about 5% to 80% of the weight of said composition, preferably from 8% to 40% by weight, antisoiling agents, anti-redeposition agents, bleaching agents, fluorescence agents, foam suppressants, softeners, enzymes and other additives.
The examples which follow are given for illustrative purposes.